package org.jflame.devAide.plugin.codeFormatter;

import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.regex.Pattern;

import org.apache.commons.lang3.StringUtils;
import org.jflame.commons.model.Chars;

public class SQLFormatter implements CodeFormatter {

    private final Set<String> BEGIN_CLAUSES = new HashSet<String>();
    private final Set<String> END_CLAUSES = new HashSet<String>();
    private final Set<String> LOGICAL = new HashSet<String>();
    private final Set<String> QUANTIFIERS = new HashSet<String>();
    private final Set<String> DML = new HashSet<String>();
    private final Set<String> MISC = new HashSet<String>();
    final String WHITESPACE = " \n\r\f\t";
    final String indentString = "    ";
    final String initial = "\n    ";

    public SQLFormatter() {
        BEGIN_CLAUSES.add("left");
        BEGIN_CLAUSES.add("right");
        BEGIN_CLAUSES.add("inner");
        BEGIN_CLAUSES.add("outer");
        BEGIN_CLAUSES.add("group");
        BEGIN_CLAUSES.add("order");

        END_CLAUSES.add("where");
        END_CLAUSES.add("set");
        END_CLAUSES.add("having");
        END_CLAUSES.add("join");
        END_CLAUSES.add("from");
        END_CLAUSES.add("by");
        END_CLAUSES.add("join");
        END_CLAUSES.add("into");
        END_CLAUSES.add("union");

        LOGICAL.add("and");
        LOGICAL.add("or");
        LOGICAL.add("when");
        LOGICAL.add("else");
        LOGICAL.add("end");

        QUANTIFIERS.add("in");
        QUANTIFIERS.add("all");
        QUANTIFIERS.add("exists");
        QUANTIFIERS.add("some");
        QUANTIFIERS.add("any");

        DML.add("insert");
        DML.add("update");
        DML.add("delete");

        MISC.add("select");
        MISC.add("on");
    }

    private class FormatProcess {

        boolean beginLine = true;
        boolean afterBeginBeforeEnd = false;
        boolean afterByOrSetOrFromOrSelect = false;
        // boolean afterValues = false;
        boolean afterOn = false;
        boolean afterBetween = false;
        boolean afterInsert = false;
        int inFunction = 0;
        int parensSinceSelect = 0;
        private LinkedList<Integer> parenCounts = new LinkedList<Integer>();
        private LinkedList<Boolean> afterByOrFromOrSelects = new LinkedList<Boolean>();

        int indent = 1;

        StringBuilder result = new StringBuilder();
        StringTokenizer tokens;
        String lastToken;
        String token;
        String lcToken;

        public FormatProcess(String sql) {
            tokens = new StringTokenizer(sql, "()+*/-=<>'`\"[]," + WHITESPACE, true);
        }

        public String perform() {

            result.append(initial);

            while (tokens.hasMoreTokens()) {
                token = tokens.nextToken();
                lcToken = token.toLowerCase();
                // System.out.println(token);
                if ("'".equals(token)) {
                    String t;
                    do {
                        t = tokens.nextToken();
                        token += t;
                    } while (!"'".equals(t) && tokens.hasMoreTokens()); // cannot handle single quotes
                } else if ("\"".equals(token)) {
                    String t;
                    do {
                        t = tokens.nextToken();
                        token += t;
                    } while (!"\"".equals(t));
                }
                if (afterByOrSetOrFromOrSelect && ",".equals(token)) {
                    commaAfterByOrFromOrSelect();
                } else if (afterOn && ",".equals(token)) {
                    commaAfterOn();
                } else if ("(".equals(token)) {
                    openParen();
                } else if (")".equals(token)) {
                    closeParen();
                } else if (BEGIN_CLAUSES.contains(lcToken)) {
                    beginNewClause();
                } else if (END_CLAUSES.contains(lcToken)) {
                    endNewClause();
                } else if ("select".equals(lcToken)) {
                    select();
                } else if (DML.contains(lcToken)) {
                    updateOrInsertOrDelete();
                } else if ("values".equals(lcToken)) {
                    values();
                } else if ("on".equals(lcToken)) {
                    on();
                } else if (afterBetween && lcToken.equals("and")) {
                    misc();
                    afterBetween = false;
                } else if (LOGICAL.contains(lcToken)) {
                    logical();
                } else if (isWhitespace(token)) {
                    white();
                } else {
                    misc();
                }

                if (!isWhitespace(token)) {
                    lastToken = lcToken;
                }

            }
            return result.toString();
        }

        private void commaAfterOn() {
            out();
            indent--;
            newline();
            afterOn = false;
            afterByOrSetOrFromOrSelect = true;
        }

        private void commaAfterByOrFromOrSelect() {
            out();
            newline();
        }

        private void logical() {
            if ("end".equals(lcToken)) {
                indent--;
            }
            newline();
            out();
            beginLine = false;
        }

        private void on() {
            indent++;
            afterOn = true;
            newline();
            out();
            beginLine = false;
        }

        private void misc() {
            out();
            if ("between".equals(lcToken)) {
                afterBetween = true;
            }
            if (afterInsert) {
                newline();
                afterInsert = false;
            } else {
                beginLine = false;
                if ("case".equals(lcToken)) {
                    indent++;
                }
            }
        }

        private void white() {
            if (!beginLine) {
                result.append(" ");
            }
        }

        private void updateOrInsertOrDelete() {
            out();
            indent++;
            beginLine = false;
            if ("update".equals(lcToken)) {
                newline();
            }
            if ("insert".equals(lcToken)) {
                afterInsert = true;
            }
        }

        private void select() {
            out();
            indent++;
            newline();
            parenCounts.addLast(Integer.valueOf(parensSinceSelect));
            afterByOrFromOrSelects.addLast(Boolean.valueOf(afterByOrSetOrFromOrSelect));
            parensSinceSelect = 0;
            afterByOrSetOrFromOrSelect = true;
        }

        private void out() {
            result.append(token);
        }

        private void endNewClause() {
            if (!afterBeginBeforeEnd) {
                indent--;
                if (afterOn) {
                    indent--;
                    afterOn = false;
                }
                newline();
            }
            out();
            if (!"union".equals(lcToken)) {
                indent++;
            }
            newline();
            afterBeginBeforeEnd = false;
            afterByOrSetOrFromOrSelect = "by".equals(lcToken) || "set".equals(lcToken) || "from".equals(lcToken);
        }

        private void beginNewClause() {
            if (!afterBeginBeforeEnd) {
                if (afterOn) {
                    indent--;
                    afterOn = false;
                }
                indent--;
                newline();
            }
            out();
            beginLine = false;
            afterBeginBeforeEnd = true;
        }

        private void values() {
            indent--;
            newline();
            out();
            indent++;
            newline();
            // afterValues = true;
        }

        private void closeParen() {
            parensSinceSelect--;
            if (parensSinceSelect < 0) {
                indent--;
                parensSinceSelect = parenCounts.removeLast()
                        .intValue();
                afterByOrSetOrFromOrSelect = afterByOrFromOrSelects.removeLast()
                        .booleanValue();
            }
            if (inFunction > 0) {
                inFunction--;
                out();
            } else {
                if (!afterByOrSetOrFromOrSelect) {
                    indent--;
                    newline();
                }
                out();
            }
            beginLine = false;
        }

        private void openParen() {
            if (isFunctionName(lastToken) || inFunction > 0) {
                inFunction++;
            }
            beginLine = false;
            if (inFunction > 0) {
                out();
            } else {
                out();
                if (!afterByOrSetOrFromOrSelect) {
                    indent++;
                    newline();
                    beginLine = true;
                }
            }
            parensSinceSelect++;
        }

        private boolean isFunctionName(String tok) {
            final char begin = tok.charAt(0);
            final boolean isIdentifier = Character.isJavaIdentifierStart(begin) || '"' == begin;
            return isIdentifier && !LOGICAL.contains(tok) && !END_CLAUSES.contains(tok) && !QUANTIFIERS.contains(tok)
                    && !DML.contains(tok) && !MISC.contains(tok);
        }

        private boolean isWhitespace(String token) {
            return WHITESPACE.indexOf(token) >= 0;
        }

        private void newline() {
            result.append(Chars.LF);
            for (int i = 0; i < indent; i++) {
                result.append(indentString);
            }
            beginLine = true;
        }
    }

    @Override
    public String convert(String source) {
        return new FormatProcess(source.replaceAll("\\s+,", ",")).perform();
    }

    @Override
    public boolean isSupported(String text) {
        text = StringUtils.replacePattern(text, "\\s{2,}", " ");
        // 宽松的正则判断是否SQL语句
        return isSelectSql(text) || isInsertSql(text) || isUpdateSql(text) || isDeleteSql(text) || isCreateSql(text);
    }

    private Pattern selectPattern = Pattern.compile("\\bselect\\s\\S+\\sfrom\\s\\S+", Pattern.CASE_INSENSITIVE);
    private Pattern insertPattern = Pattern.compile(
            "\\b(insert|repalce)\\b\\sinto\\s\\S+\\s*(\\(\\S+(\\s*,\\s*\\S+\\s*)*\\))?\\s+values\\s*(\\(\\S+(\\s*,\\s*\\S+\\s*)*\\))",
            Pattern.CASE_INSENSITIVE);
    private Pattern updatePattern = Pattern.compile(
            "\\bupdate\\s\\S+\\s\\bset\\s+\\S\\s*=\\s*\\S(\\s*,\\s*\\S\\s*=\\s*\\S)*", Pattern.CASE_INSENSITIVE);
    private Pattern delPattern = Pattern.compile("delete\\s(\\w+\\s)*\\bfrom\\s\\S+", Pattern.CASE_INSENSITIVE);
    private Pattern createPattern = Pattern.compile("create\\stable\\s\\S+\\(\\S+\\s*\\)", Pattern.CASE_INSENSITIVE);

    private boolean isSelectSql(String text) {
        return selectPattern.matcher(text)
                .find();
    }

    private boolean isUpdateSql(String text) {
        return updatePattern.matcher(text)
                .find();
    }

    private boolean isInsertSql(String text) {
        return insertPattern.matcher(text)
                .find();
    }

    private boolean isDeleteSql(String text) {
        return delPattern.matcher(text)
                .find();
    }

    private boolean isCreateSql(String text) {
        return createPattern.matcher(text)
                .find();
    }

    @Override
    public String getCodeFormat() {
        return "SQL";
    }

}
